-LRB- CNN -RRB- -- The leader of Colombia 's main leftist rebel group -- the Revolutionary Armed Forces of Colombia -- died in a military operation in the country 's southwest , President Juan Manuel Santos said Saturday .

`` I confirm the death of Alfonso Cano . The No. 1 of FARC is dead , '' Santos said . `` This is the most overwhelming blow given to the FARC in all of Colombia 's history . ''

The military operation that took place Friday in the state of Cauca also killed Cano 's communications chief , a female friend and members of his security team , Defense Minister Juan Carlos Pinzon told reporters . Cano 's chief of security was captured .

`` The death of Alfonso Cano is the most important historical mark of our military forces and our national police in our fight against the FARC organization , '' Pinzon said . `` He was part of the organization for over 33 years . He was their ideologue , their political figure and most importantly , he was a despised terrorist ready to act in a radical way ... ''

Cano , an alias for Guillermo Leon Saenz , took over the FARC 's top spot in March 2008 after an apparent heart attack killed the former leader , Manuel Marulanda .

Cano 's family released a statement following his death , urging peace and asking the media to respect their privacy . They called on authorities in Colombia , and specifically on President Santos , to allow them the opportunity to give Cano a dignified burial .

`` This is great news for all the Colombian people , '' said Labor Minister Rafael Pardo . `` This will help the peace process and it shows that armed conflict is no longer the way forward in Colombia . ''

The FARC has been at war with the Colombian government since the 1960s . While severely weakened in recent years , the guerrilla group has continued to carry out kidnappings and attack security forces in the South American nation .

Following Cano 's death , the FARC released a statement in which its leaders said they would not end their guerrilla struggle .

`` This is not the first time that the oppressed and exploited in Colombia are mourning one of its greatest leaders . Nor is it the first -LRB- time -RRB- that he will be replaced with the courage and absolute conviction of victory . Peace in Colombia will not be born in any guerrilla demobilization , but the abolition of the causes that give birth the upheaval , '' they wrote .

Senior officials in the administration of U.S. President Barack Obama said that they believe Cano 's death will pose a serious challenge to the FARC going forward . There are n't many people left to head the group and most of those who might , no longer live in Colombia , they said .

The FARC , which began as a revolutionary guerrilla group , has evolved into a narco-trafficking organization , the officials said . While it is no longer able to threaten the state , the FARC still has the potential to hurt a lot of people , they added .

The United States and European Union consider the FARC a terrorist organization .

`` This is an important victory for Colombia and represents a major blow against the largest terrorist organization in this hemisphere , '' said U.S. State Department spokeswoman Darla Jordan .

`` We firmly support the efforts of the Colombian people , their security forces , and President Santos to combat the FARC , '' she said .

In July , Santos said Cano escaped an attack by less than a day . At the time , security forces raided a remote camp believed to have been his hideout . After the raid , authorities found clothes they believe belonged to Cano .

CNN affiliate Caracol TV reported that authorities also found large quantities of the cigarettes the FARC leader is thought to smoke .

`` We were very close , '' the president told reporters at a military airport in Bogota .

He said security forces had acted on an intelligence tip from one of Cano 's `` own people . ''

CNN 's Claudia Dominguez , Luis Carlos Velez and Elise Labott contributed to this report .

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NEW : The FARC says his death does not spell the end of the guerrilla struggle

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The FARC leader 's family asks that his remains be treated with dignity

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Alfonso Cano took over the FARC 's top spot in 2008

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President says security forces missed the leader by less than a day in July